The synthesis of 6-R-4-hydroxy-1,2,3,4-tetrahydroquinoline-3-carboxylic acids and 6-R-1,2,3,4-tetrahydroquinoline-3,4-dicarboxylic acids is proposed. The molecules are to be separated into geometric isomers and evaluated as inhibitors of lactic acid dehydrogenase and malic acid dehydrogenase. Several compounds will be selected for investigations aimed at separation of optical isomers. The results of these studies will be utilized in the design of selective inhibitors of anaerobic and aerobic tumor cell respiration as potential antineoplastic agents.